Signaling System No. 7 (SS7) is a global standard for telecommunications. The standard defines the procedures and protocol by which network elements in the public switched telephone network (PSTN) exchange information over a digital signaling network to effect wireless (cellular) and wired call setup, routing and control. The SS7 network and protocol are used for, among others, basic call setup and toll-free (800/888) and toll (900) wired services.
Due to potential liability for placing calls to numbers on the Do Not Call Registry, the easy and inexpensive determination of whether a particular number is on the Do Not Call Registry has become a priority to businesses and an economic burden to small business entities due to complex adaptations previously required to their SS7 networks. Prior solutions to the problem of obtaining phone numbers on the Registry involved obtaining outdated lists or developing complex internal networking adaptations to connect to the list which often involved checking a number prior to calling or crosschecking a series of numbers. These solutions were either time consuming or expensive or both.